package com.twenty.seven.toolbox.encrypt.symmetry;

import org.apache.commons.codec.binary.Base64;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

/**
 * @Author 001
 * @Date 2020/1/7 11:37
 * @TODO AES算法加密
 **/
public class AESUtil {
    /**
     * 默认的加密算法
     **/
    private static final String KEY_ALGORITHM = "AES";
    private static final String DEFAULT_CIPHER_ALGORITHM = "AES/ECB/PKCS5Padding";

    /**
     * AES 加密操作
     *
     * @param content 待加密内容
     * @param key     加密密钥
     * @return 返回Base64转码后的加密数据
     */
    public static String encrypt(String content, String key) throws Exception {
        // 创建密码器
        Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);

        byte[] byteContent = content.getBytes("utf-8");
        // 初始化为加密模式的密码器
        cipher.init(Cipher.ENCRYPT_MODE, getSecretKey(key));
        // 加密
        byte[] result = cipher.doFinal(byteContent);
        //通过Base64转码返回
        return Base64.encodeBase64String(result);
    }

    /**
     * AES 解密操作
     *
     * @param content
     * @param key
     * @return
     */
    public static String decrypt(String content, String key) throws Exception {

        //实例化
        Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);

        //使用密钥初始化，设置为解密模式
        cipher.init(Cipher.DECRYPT_MODE, getSecretKey(key));

        //执行操作
        byte[] result = cipher.doFinal(Base64.decodeBase64(content));

        return new String(result, "utf-8");
    }

    /**
     * 生成加密秘钥
     *
     * @return
     */
    private static SecretKeySpec getSecretKey(final String key) throws NoSuchAlgorithmException {
        //返回生成指定算法密钥生成器的 KeyGenerator 对象
        KeyGenerator kg = null;

        kg = KeyGenerator.getInstance(KEY_ALGORITHM);

        //AES 要求密钥长度为 128
        kg.init(128, new SecureRandom(key.getBytes()));

        //生成一个密钥
        SecretKey secretKey = kg.generateKey();
        // 转换为AES专用密钥
        return new SecretKeySpec(secretKey.getEncoded(), KEY_ALGORITHM);

    }

    public static void main(String[] args) throws Exception {
        String content = "hello,您好";
        String key = "sde@5f98H*^hsff%dfs$r344&df8543*er";
        System.out.println("content:" + content);
        String s1 = AESUtil.encrypt(content, key);
        System.out.println("s1:" + s1);
        System.out.println("s2:" + AESUtil.decrypt(s1, key));

    }

}
